Per user mail sending restriction implementation

Hello Guys,

I want to prevent the user from sending emails to only some white listed emails. Now, those white list would be different for each and every users on zimbra and which should be dynamically changeable. Can anybody just guide me how I can achieve that. I've studied postfix but it doesn't support user based ACLs. Please help me.

kind of solved

We did manage to solve part of this issue by following the procedure listed in Restrict sending to certain domains - Zimbra :: Wiki instead of passing the mydomain.com as allowed we rectricted it and then put a rule to on each and every account to be checked.
I will be posting the entire script and procedure by the end of the week after we have the entire server setup. Its been a pain applying the security on each and every account (750 mail boxes) with management being allowed to send to all domains and groups etc.
Hope this is passed by the IT audit team or else :-( i have no idea what do

We did manage to solve part of this issue by following the procedure listed in Restrict sending to certain domains - Zimbra :: Wiki instead of passing the mydomain.com as allowed we rectricted it and then put a rule to on each and every account to be checked.
I will be posting the entire script and procedure by the end of the week after we have the entire server setup. Its been a pain applying the security on each and every account (750 mail boxes) with management being allowed to send to all domains and groups etc.
Hope this is passed by the IT audit team or else :-( i have no idea what do